Before freeserv existed in the UK we didn't have a flat rate and a 800 number you could call into, you dialed a local number and paid by the minute, mum limited me to 2 hours a day and the she would take the RJ9 cable to enforce it.
One afternoon at lunch break at school I went down to the local elections store and used 2 days worth of lunch money to buy a secret RJ9.
After mum went to bed I'd sneak out my cable and dial up, spend all night online and hide it again in the morning.
Well... I ran up a 500 pound bill, I came home from school at the end of that month to a furious mum crying because we certainly couldn't afford it.
Mum called BT and explain what I'd done, and that it was unauthorized use, thank god BT nulled my contraband internet usage but it was a valuable lesson in doing as your parents say.
Really really really greatful freeserv popped up, although they eventually banned me for abusing "unlimited" (then I just got my uncle to create a new account for me).